Sir Isaac Newton, Laws of Motion
Sir Isaac Newton was an English physician that defined the universal gravitation. He is considered by many people to be the greatest scientist of all time. He was the one who gave birth to modern physics. The most important contribution were his three laws of motion, which are Law of Inertia, Law of Force and Acceleration, and Law of Action and Reaction and the Law of Gravity.
Before Newton and Galileo, most people thought that the forces causing motions on Earth and the forces causing the stars and planets to move were different forces. Isaac Newton realized that the same forces and the same laws of physics apply everywhere in the universe. So, Newtons law of gravity is called the law of universal gravitation. There are two things that affect gravity attraction: distance and mass. If the mass decreases so will the force of gravity, however if it increases, the force of gravitation will increase.
The first Law of Motion or Law of Inertia
The Law of Inertia uses forces and changes in velocity. It states that an object at rest will remain at rest unless an unbalanced force contacts it. An object in motion will continue in motion with the same speed and in the same direction unless acted upon by an unbalanced force. An object at rest is just a special case of an object that is maintaining constant velocity. Its velocity is constantly 0 m/s.
The second Law of Motion or Law of Force and Acceleration
According to Newtons second Law of Motion, acceleration is produced when a force acts on a mass. The greater the mass of the object being accelerated, the greater the amount of force needed to accelerate the object. When an unbalanced force acts upon an object, the motion of the object will change, and the level of this change is called acceleration. This law explains how the velocity of an object changes when it is exposed to an external force.